Stabilized acetaldehyde and method



Patented Dec. 24;, 1946 STABILIZED ACETALDEHYDE AND'LETHOD Joseph GrayDinwiddie, Waynesboro, Va., assignor to E. I. du Pont de Nemours &Company,

Wilmington,

Del, a corporation of Delaware No Drawing. Application August 20,1943,Serial No. 499,405

Claims. (Cl. 260-601) This invention relates to the stabilization ofacetaldehyde or acetaldehyde-containing liquors against polymerizationduring storage and distillation.

copper resinate is added and the acetaldehyde so treated set aside for astorage test. ,After 5 weeks, a sample of the acetaldehyde was tted mer.

and was found to contain less than 2% of poly- A similar sample ofacetaldehyde used as a control was found to contain, under the sameconditions of testing, about of polymer.

Acetaldehyde, when kept in storage for any 5 While the specific exampleillustrates the stalength of time, tends to polymerize and formbilization of pure or substantially pure acetaldepolymeric products,such as paraldehyde and hyde, it is to be understood that the inventionis metaldehyde, which generally are undesirable. not so limited butcomprehends too the stabiliza- Also, distillation and rectification ofacetaldehyde tion of acetaldehyde-conta n q s W ch or liquors consistingpredominantly of acetalde- 19 comprise in addition, water, acetic acidand/or hyde is accompanied by a rapid conversion of other misciblesubstance but which consist preacetaldehyde into'polymeric form.-dominantly of acetaldehyde. 1

Accordingly, it is an object of this invention to The chief advantagesof my invention are that provide a polymerization inhibitor which is411- the stabilizing agents r in p i di y rectly soluble in theacetaldehyde and which can 15 tainable, and can be easily and complet yr be easily separated'from the acetaldehyde, for covered from theacetaldehyde for reuse it deinstance, by redistilllng the acetaldehydeat the d. and t v y stabilize the ac ta d yd time it is to be used.Other objects of the inunder all conditions for long periods of time.vention will be apparent from the description that AS many Widelydlfierent embodiments f t follows. 7 2o invention may be made withoutdeparting from The objects of this invention are accomplished the Spiritand c p e it 15 to be underby incorporating in acetaldehyde before,during stood that the invention is not limited to the speand/or afterrectification a small amount of a 01116 embodiments thereof eXe Ptasdefined in the soluble metal resinate, such as the copper, zinc, pp n dclaimsaluminum, magnesium and cobalt resinate. I claim:

Metal resinates of commerce are essentially 1. A method for inhibitingPolymerization o abietates containing various impurities and acet ld yduring stora e a d d stil tion varying within relative smallproportions. Since which comprises incorporating in an acetalde-- metalresinates of commercial grades are entirely hyde-containing solution asmall amount of a satisfactory for the purpose of the presentinven- 80metal resinate soluble in said solution.

151011 and considerably more economical than 2. A method for inhibitingpolymerization of metal abietates, it is preferred to use them as aacetaldehyde during storage and m nu n matte! of economy and conveniencewhich comprises incorporating in an acetaldenly a v ry s a l amount f su ta yde-containing solution from about 0.01% to inate is needed toeffect substantial stability of 85 about 1.0% by weight, based on theweight of aceta de yd for p as ittl s .0 of acetaldehyde, of a metalresinate soluble in said copper resinate, based-on the weight oi theacetol tion, aldehyde treated will very noticeably improve the 3. Amethod for inhibiting polymerization of stability of the acetaldehyde.However, under acetaldehyde during storage and distillation certaincircumstances, it may be desirable to use which comprises incorporatingin an acetaldeup to 1% of the soluble metal resinate.Generhyde-containing solution about 0.1% by weight,- ally about 0.1% ofsoluble metal resinate based based on the weight of acetaldehyde, of ametal on the weight of the acetaldehyde is preferred. resinate solublein said solution.

To further illustrate this invention, the followg 4, A method forinhibiting polymerization of p fi exampleis giveh- Parts and p cacetaldehyde during storage and distillation a e compositions are byweight unless otherwise which comprises incorporating in saidacetaldeindicated. hyde about 0.1% by weight, based on the weight l kample of acetaldehyde, of copper resinate.

To 1000 p rt of acetaldehyde freshl 5. A composition comprisingessentially acetdensed from the rectification column, 1 part of aldehyden rom b ut 0.01% to about 1.0%

by weight, based on the weight of acetaldehyde, of a soluble metalreslnate.

